Compact twistless multifilament yarn bundle



Feb. 10, 1970 L. H. P. WEL'DON 3,494,822

COMPACT TWISTLESS MULTIFILAMENT YARN BUNDLE Filed May 23, 1966 2Sheets-Sheet 1 I n ma n lor imwepfiwrzriimaeM-"mwy A ltorneys Feb. 10,1970 1.. H. PQWELDON 3,494,322

COMPACT TWISTLESS MULTIFILAMENT YARN BUNDLE Filed May 23, 1966 2Sheets-Sheet 2 waif 4.4

A llorneys United States Patent 3,494,822 COMPACT TWISTLESSMULTIFILAMENT YARN BUNDLE Leonard Harvey Pocock Weldon, Penarth, Wales,assignor to Imperial Chemical Industries Limited, London, England, acorporation of Great Britain Filed May 23, 1966, Ser. No. 552,193 Claimspriority, applicat2i7on G0r}e6a5t Britain, June 28, 1965,

9 Int. Cl. D02g 3/00; D04h 1/04 US. Cl. 161172 2 Claims ABSTRACT OF THEDISCLOSURE A twistless compact multifilament yarn bundle is disclosed,consisting of a plurality of non-adhesive continuous filaments and asingle potentially adhesive monofilament which effects interfilamentarycohesion.

The invention concerns improvements in or relating to com-pact filamentbundles and their production.

By the expression filament bundles we mean a colleo tion of a pluralityof filaments forming a distinct entity, whether of yarn or of tow denierand by compact we mean that the filaments of the filament bundle areclosely bound to one another such that the filament bundle ismanipulable as an entity.

conventionally, filament bundles have been rendered compact by theinsertion of twist. The rate of yarn production, for instance, ishowever limited by the capability of the twist-inserting agency; and ithas long been recognised that there are advantages of productivity to begained from the employment of twistless yarns, so long as these can behandled satisfactorily in subsequent textile processes, as for instanceweaving and warp-knitting. In addition, twistless yarns can addstructure and textural characteristics of their own to fabrics.

Thus, proposals have been made for other restraints on filamentseparation, apart from twist.

Filament intermingling by air jet has been one such proposal, for towand yarn. Alternating S and Z twist, which can be inserted more rapidlythan uni-directional twist, has been another; and filament adhesion hasbeen another.

In one process of the latter proposal, fibres or filaments of anadhesion promoting substance have been mixed, in a minor proportion,with fibres or filaments of the basic material of the filament bundle,and then the adhesion promoting filaments have been activated, as by theapplication of heat to the bundle, to cause adhesion between all thefilaments at the points of their intersection via the activated adhesionpromoting filaments.

It is with improved compact filaments bundles, of the type containingadhesion promoting filaments, and with a process for their production,that this invention is principally concerned.

According to the invention, a compact filament bundle comprises a majorproportion by weight of the bundle of non-adhesive continuous filaments,said filaments being adhered to one another at some, at least, of theirpoints of intersection by an adhesive portion of a potentially adhesivemonofilament that has been rendered adhesive, said monofilamentcomprising a minor proportion by weight of the bundle.

Preferably, the compact filament bundle has zero bundle twist and has ahook drop distance, as defined in British Patent Specification 924,089,of less than 10 cms.

The effect of the presence of the adhesive monofilament is essentiallythat of spot welding the other filaments at the affected points of theirintersection. This selective effect is not obtained according to theprior proposals in which the filament bundle is composed of a pluralityof each kind of filament.

The preferred potentially adhesive monofilament is heatactivateable; andthe method of activating it is by heating the composite filament bundleto a temperature insuflicient to soften the basic (non-adhesive)filaments and sufficient to cause the potentially adhesive monofilamentto soften and become tacky without, however, breaking at the tension oftreatment of the filament bundle.

The invention will now be described by reference to the followingdiagrammatic drawings, in which FIGURE 1 shows a portion of amultifilament yarn according to the invention; and

FIGURE 2 shows the lay-out of apparatus and the thread-lines used in amethod of making a preferred yarn according to the invention.

In FIGURE 1, a potentially adhesive monofilament 1 is shown to beadhered to certain of a plurality of non-adhesive filaments 3 at theirpoints of mutual contact. The filament bundle is shown in openedcondition, for the sake of clarity; but the yarn according to theinvention will, in fact, have the non-adhesive filaments adhering to oneanother at points Where they themselves intersect.

In FIGURE 2, a packaged supply 5 of a potentially adhesive monofilament1 is mounted for free withdrawal of the monofilament therefrom throughthread-guide 7; and a packaged supply 9 of a twistless multifilamentyarn 11 comprising non-adhesive filaments is mounted for free withdrawalof the yarn therefrom through the same thread-guide.

The yarn and the monofilament are intimately combined at thethread-guide 7, and the combined structure is pulled, under theinfluence of the driven wind-up 13, through a heater tube 15, in whichthe potentially adhesive monofilament is rendered adhesive by heat so asto produce a compact composite yarn 17 which is then wound up in apackage 19.

The invention will be further described without limitation by thefollowing examples, in each of which a strand of the basic filaments ofnylon 66 (polyhexamethylene adipamide) is combined with one of severalpotentially adhesive monofilaments and the composite filament bundle istreated by heat on passage through a heated zone.

EXAMPLE 1 Zero twist 205 34 nylon 66 yarn and a single 70 denierfilament of a 65/35 polyester/polyurethane copolymer (as described inUS. Patent 3,357,954) having a softening range of 135-165" C. (Vicat)were passed together through a guide at 72 feet per minute and thenthrough an electrically heated jacket set at such a temperature as wouldjust fail to cause the monofilament to break.

The composite yarn after this treatment had a hook drop test distance of6 cm., compared with a distance of over cms. for the Zero twist supplyyarn.

EXAMPLE 2 Zero twist 205/34 nylon 66 yarn was combined as in Example 1with a single 36 denier filament of the same polymer as in Example 1 andwas then passed through an electrically heated jacket set at atemperature determined as in Example 1. It was observed that thetemperature of the air around the yarn near the middle of the heater was320330 C.

The composite yarn after this treatment had a hook drop test distance of4 cms.

EXAMPLE 3 Zero twist 205/34 nylon 66 yarn and a single 15 denierfilament of nylon 6 (polycaprolactam) having a softening range of around210-220 C. were combined and treated as in Example 1, the temperature ofthe heater being determined by the same criterion.

The composite yarn after this treatment had a hook drop test distance ofcms.

EXAMPLE 4 Zero twist 205/ 34 nylon 66 yarn and a single denier filamentof nylon 6 were combined and treated as in EX- ample 3. It was observedthat the temperature of the air around the yarn near the middle of theheater was 330- 360 C.

The composite yarn after this treatment had a hook drop test distance of8 cms.

EXAMPLE 5 Yarns as in Example 4 were combined and treated in the sameway with the heater set at a slightly lower temperature. The airtemperature observed as in Example 4 was 315340 C.

The composite yarn after this treatment had a hook drop test distance ofcms.

EXAMPLE 6 Zero twist 205/34 nylon 66 yarn and a single 15 denierfilament of a 50/50 copolymer of nylon 66 and nylon 6.10 having asoftening point of around 170 C. were combined and heated as inExample 1. The air temperature observed as in Example 2 was 290-310 C.

The composite yarn after this treatment had a hook drop test distance of4 cms.

It is to be understood that the invention is not limited to nylon 66filaments as the basic ones of the filament bundle; nor to potentiallyadhesive monofilaments which are activateable by heat, or by heat alone,as in the above Examples.

Any material in continuous filament form can constitute the basicfilaments, although normally the invention will be of greatestapplication in respect of synthetic materials, such as those of the highmolecular weight synthetic polymers, namely polypropylene, polyethyleneterephthalate and polyarcylonitrile.

The potentially adhesive monofilaments may be rendered adhesive by, forinstance, the application of pressure in addition to heat, as by passingthe composite filament bundle through pressure rollers; or they may berendered adhesive by selective chemical treatment.

If it is desired to combine activation with lengthwise contraction(relaxation) of the basic filaments of the yarn, then conveniently thecombined treatment may be effected by passing the yarn through aturbulent zone in a jet to which a hot gaseous fluid, such as steam orhot air, is supplied. Such a requirement may well be present in theproduction of multifilament yarns of nylon for weaving; and thetreatment may conveniently be carried out on the yarn immediately afterdrawing and prior to winding.

What I claim is:

1. A campact multifilament yarn bundle consisting of a plurality ofnon-adhesive continuous filaments and a single potentially adhesivemonofilament, said nonadhesive filaments being adhered to one another atsome, at least, of their points of intersection by an adhesive portionof said potentially adhesive monofilament that has been renderedadhesive, said non-adhesive continuous filaments constituting a majorportion, by weight, of the bundle, and said potentially adhesivemonofilament constituting a minor proportion by weight of the filamentsaid compact yarn bundle having substantially zero bundle twist and ahook drop distance of less than ten centimeters.

2. A compact multifilament bundle as claimed in claim 1 of which thepotentially adhesive monofilament has a softening temperature below thatof the non-adhesive continuous filaments.

References Cited UNITED STATES PATENTS 2,500,282 3/1950 Francis 161-1502,688,380 9/1954 MacHenry 183-44 2,812,767 11/1957 MacHenry 131-102,979,433 4/1961 MacHenry 156-159 3,144,025 8/ 1964 Erlich 131-2643,388,030 6/1968 Estes et a1 161-172 ROBERT F. BURNETT, Primary ExaminerL. M. CARLIN, Assistant Examiner US. Cl. X.R. 161-15 0

